xref: /illumos-gate/usr/src/lib/libc/port/gen/dirname.c (revision 7257d1b4)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 /*
33  *	Return pointer to the directory name, stripping off the last
34  *	component of the path.
35  *	Works similar to /bin/dirname
36  */
37 
38 #pragma weak _dirname = dirname
39 
40 #include "lint.h"
41 #include <sys/types.h>
42 #include <string.h>
43 
44 char *
dirname(char * s)45 dirname(char *s)
46 {
47 	char	*p;
48 
49 	if (!s || !*s)			/* zero or empty argument */
50 		return (".");
51 
52 	p = s + strlen(s);
53 	while (p != s && *--p == '/')	/* trim trailing /s */
54 		;
55 
56 	if (p == s && *p == '/')
57 		return ("/");
58 
59 	while (p != s)
60 		if (*--p == '/') {
61 			while (*p == '/' && p != s)
62 				p--;
63 			*++p = '\0';
64 			return (s);
65 		}
66 
67 	return (".");
68 }
69